Contact assembly for electric watches

ABSTRACT

A contact spring assembly for an electric watch comprises an elongated contact spring which intermittently engages a contact pin on the balance wheel. The contact spring is fixedly mounted at one end to a base member and damped to eliminate undesirable oscillations by positioning a spring portion located a predetermined distance from the end in a slotted member. The spring portion in the slot is surrounded by a material which dampens the vibrations of the spring as the free end contacts the pin during the oscillations of the balance wheel.

United States Patent Kaulins 51 Oct. 17,1972

[54] CONTACT ASSEMBLY FOR ELECTRIC WATCHES [72] Inventor: Edward Kaulins, New Milford,

Conn.

[73] Assignee: Timex Conn.

[22] Filed: July 20, 1970 [2]] Appl. No.: 62,302

Corporation, Waterbury,

[52] US. Cl. ..58/28 R, ZOO/61.39 [51] Int. Cl. ..G04c 3/04, HOlh SH 6 [58] Field of Search,....58/23, 28 A, 28 B, 28 D, 107;

[56] References Cited UNITED STATES PATENTS Wathick ..58/28 Primary Examiner-Richard B. Wilkinson Assistant Examiner-Edith C. Simmons Jackmon Attorney-Richard A. Joel [5 7 ABSTRACT A contact spring assembly for an electric watch comprises an elongated contact spring which intermittently engages a contact pin on the balance wheel. The contact spring is fixedly mounted at one end to a base member and damped to eliminate undesirable oscillations by positioning a spring portion located a predetermined distance from the end in a slotted member. The spring portion in the slot is surrounded by a material which dampens the vibrations of the spring as the free end contacts the pin during the oscillations of the balance wheel. 7, 7

6 Claims, 3 Drawing Figures CONTACT ASSEMBLY FOR ELECTRIC WATCHES BACKGROUND OF THE INVENTION The present invention relates to timekeeping devices and more particularly to a contact spring assembly for an electric watch.

In conventional electric watches, the contact spring vibrates after engaging the contact pin. This vibration is generally undesirable and, to eliminate the possibility of malfunction, the spring must be adjusted extremely accurately and its functional length maintained within close tolerance. In some watch designs, damping of the contact spring is necessary for proper functioning. By positioning an intermediate portion of the contact spring in a slotted member and surrounding that portion with a selected damping material, it is possible to dampen the spring in an expeditious and inexpensive manner. The subject assembly also significantly reduces the required adjustment to the contact spring and reducesthe possibility of handling damage which often occurs when the balance wheel is turned manually with the spring caught on the pin or between the jewel and pin.

The prior art is represented by U.S. Pat. Nos. 2,004,610 and 2,166,326 which disclose the broad concept of coating and element to dampen vibrations. The prior art does not appear to disclose specific novel arrangements of the type disclosed herein.

SUMMARY OF THE INVENTION The present invention relates to a contact spring assembly for an electric watch comprising an elongated contact spring affixed at one end to a base member with the other end free to engage a contact pin on an oscillating balance wheel. A slotted or grooved portion of the base extends outwardly therefrom with a portion of the contact spring extending through the groove a predetermined distance from the fixed end. The spring portion within the groove is surrounded or potted with a selected damping material to reduce spring vibrations after contact with the contact pin. The damping material can be readily and inexpensively applied in a controlled amount about the spring. This damping reduces time-consuming spring adjustments and the possibility of handling damage. The spring length may also be reduced resulting in a decrease in current consumption and an increase in motor efficiency.

Accordingly, it is an object of this invention to provide a new and improved contact spring assembly for an electric watch.

Another object of this invention is to provide a new and improved contact spring assembly for a watch wherein a particular damping means is provided to minimize vibrations of the spring.

Other objects and advantages of the present invention will be more clearly seen when viewed in conjunction with the accompanying drawings wherein:

FIG. 1 is a top schematic view of the contact spring assembly illustrating the cooperation of the spring with the balance wheel mounted pin;

FIG. 2 is a perspective view of the new and improved contact spring assembly comprising the present invention; and

FIG. 3 discloses an alternate mounting arrangement for the contact spring in a contact spring assembly.

DETAILED DESCRIPTION OF THE INVENTION As shown in FIG. 1 of the drawings, an electric watch includes a balance wheel 10 having a substantially annular outer rim 11 and a spoke 12 extending inwardly from the rim 11 and terminating in yoke portion 13. A balance coil 14 is mounted between the arms 16 and 17 of the yoke 13 to cooperate with fixed magnets (not shown) in the functioning of the electrical circuit for the watch. Since such electrical circuits are well-known in the art, they will not be described in detail herein.

A contact pin 18 and a contact jewel 19 are also mounted on the yoke 13 near the balance staff axis 21. The contact assembly 20 cooperates with the contact pin 18 and jewel 19 during the oscillation of the balance wheel 10 to complete the electrical circuit and provide an impulse to the balance wheel 10.

The contact assembly 20 includes a contoured base 22 of a plastic material such as dacron fiber-filled diallyl ortho-phthalate resin. A contact member 23 comprising curved metal strip portion 24, an intermediate portion (not shown) and a narrow mounting portion 26 is moulded within the base 22 with the portions 24 and 26 extending outwardly from substantially opposite portions of the base 22. The mounting portion 26 includes an end section 27 which is arranged generally perpendicular to the main body of mounting portion 26 of the contact member 23 to facilitate attachment of contact spring 28 thereto.

The spring 28 is mounted to the end section 27 of contact member 23 by means such as soldering. A protruding portion 29 extends outwardly from the base 33 and includes a slot 31 within which an intermediate section of the spring 28 is held in a damping material 32 such as Chem-O-Sol manufactured by the Chemical Products Corporation of East Providence, Rhode Island. It is to be understood of course that other damping materials having similar properties which would minimize the vibrations of the contact spring 28 may also be satisfactory. Since the slot 31 has an open upper end the spring 28 may be readily potted with a damping material 32. Ideally, the slot 31 should be spaced as close to the fixed end of spring 28 as possible.

While the invention is illustrated above in one preferred embodiment, other variations may be envisioned within the scope of the present invention. For example, the slot 31 and, in fact, the mounting portion 26 of member 23 may be shaped in a number of suitable configurations. In FIG. 3, a member 35, which includes an upright portion 33 curving inwardly to a U- shaped slotted portion 34 is affixed to the mounting portion of contact member 23 with solder 36. As a further embodiment, it may be possible to eliminate the base portions of FIG. 2 entirely and coat the end portion of spring 28 with plastic in the area of mounting section 27.

In operation, the balance wheel 10 oscillates bringing the contact spring 28 into engagement with the contact pin 18. The instant the contact spring 28 touches the contact pin 18, fixed on the balance 10, current flows through the balance drive coil 14. The current induces a magnetic field which opposes the field of a fixed magnet (not shown). The opposition of the magnetic fields imparts an impulse to the balance 10 when the magnet is in place.

The purpose of the contact jewel 19 is to limit the physical contact between the contact pin 18 and the contact spring 28 so that the flow of electrical energy occurs at a precise position during the rotation of the balance. With the present invention the spring 28 can be shortened since there is little likelihood that no con tact will be made due to the vibrations of the spring 28. Shortening the spring lessens changes of stubbing the tip of the spring 28 on the contact jewel 19. With a shorter spring, there is the possibility of a reduction in current consumption and a gain in motor efficiency.

Damping of the contact spring 28 minimizes the vibrations of the spring after contact with the pin 18 jewel 19 arrangement. With the present invention which includes a damped spring 28, the adjustment of the spring 28 can be decreased and the tolerances on its functional length need not be controlled quite so strictly.

It is to be understood that the above-described arrangements are merely illustrative examples of the application of the principles of the invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

I claim:

1. A contact spring assembly for timepieces comprising:

a contoured base,

a contact member embedded within the base and extending outwardly therefrom.

a contact spring having a free end and being mounted to the contact member,

a damping material arranged about a portion of the contact spring to minimize the vibrations thereof, and wherein the base includes an outwardly projecting portion having a slot formed therein, said contact spring extending through the slot and having the damping material arranged thereabout within the slot.

2. A contact spring assembly for timepieces comprising:

a contoured base,

a contact member embedded within the base and extending outwardly therefrom,

a contact spring having a free end and being mounted to the contact member,

a damping material arranged about a portion of the contact spring to minimize the vibrations thereof, and wherein the contact member includes a body portion and an end portion comprising a mounting portion and a slotted portion, the contact spring being affixed to the mounting portion and having the damping material arranged thereabout in the slotted portion.

3. A contact spring assembly for timepieces comprising:

a contoured base,

a contact member embedded within the base and extending outwardly therefrom,

a contact spring having a free end and being mounted to the contact member, and

a damping material arranged about a portion of the contactspring to minimize the vibrations thereof, the damping material comprising a plastic material assembled about one end of the contact spring, said end being mounted to the contact member. 4. A contact spring assembly in accordance with claim 1 wherein:

the contact member includes a relatively narrow body portion and an end portion extending at an angle thereto to facilitate mounting of one end 0 the contact spring, and the projecting portion of the base is speed in close proximity to the contact member to dampen the spring near the end thereof. 5. A contact spring assembly in accordance with claim 2 wherein:

the end portion of the contact member comprises a mounting area for one end of the contact spring and an off-set slotted portion for the contact spring, the spring being potted with a damping material within the groove to minimize vibrations and said slotted portion being in proximity to the mounting area. 6. A contact spring assembly in accordance with claim 1 wherein:

the damping material adheres to the walls of the slot and the contact spring to form an integral assembly, said material being readily deposited within said slot and about the contact spring.

* IF i 

1. A contact spring assembly for timepieces comprising: a contoured base, a contact member embedded within the base and extending outwardly therefrom. a contact spring having a free end and being mounted to the contact member, a damping material arranged about a portion of the contact spring to minimize the vibrations thereof, and wherein the base includes an outwardly projecting portion having a slot formed therein, said contact spring extending through the slot and having the damping material arranged thereabout within the slot.
 2. A contact spring assembly for timepieces comprising: a contoured base, a contact member embedded within the base and extending outwardly therefrom, a contact spring having a free end and being mounted to the contact member, a damping material arranged about a portion of the contact spring to minimize the vibrations thereof, and wherein the contact member includes a body portion and an end portion comprising a mounting portion and a slotted portion, the contact spring being affixed to the mounting portion and having the damping material arranged thereabout in the slotted portion.
 3. A contact spring assembly for timepieces comprising: a contoured base, a contact member embedded within the base and extending outwardly therefrom, a contact spring having a free end and being mounted to the contact member, and a damping material arranged about a portion of the contact spring to minimize the vibrations thereof, the damping material comprising a plastic material assembled about one end of the contact spring, said end being mounted to the contact member.
 4. A contact spring assembly in accordance with claim 1 wherein: the contact member includes a relatively narrow body portion and an end portion extending at an angle thereto to facilitate mounting of one end of the contact spring, and the projecting portion of the base is speed in close proximity to the contact member to dampen the spring near the end thereof.
 5. A contact spring assembly in accordance with claim 2 wherein: the end portion of the contact member comprises a mounting area for one end of the contact spring and an off-set slotted portion for the contact spring, the spring being potted with a damping material within the groove to minimize vibrations and said slotted portion being in proximity to the mounting area.
 6. A contact spring assembly in accordance with claim 1 wherein: the damping material adheres to the walls of the slot and the contact spring to form an integral assembly, said material being readily deposited within said slot and about the contact spring. 